I terminated several pairs of speaker cables with banana connectors and want to add shrink tubing at the union of the connectors and cable. I am looking for 3:1 shrink tubing in both black and red in 1/2" diameter. I figure 3' of it would meet my needs. I found a few sellers on-line, but either they require a minimum dollar purchase or the smallest quantity they offer is far more than my need. Can somebody recommend a source for such a small quantity? Thanks very much.

I realize that the OP found what he needed, but in case this helps anyone else ...

A few months ago, I replenished my inventory of 3:1 adhesive backed heat shrink from the folks below.

I ordered quite a bit, but I believe their minimum quantity is consistent with your needs (i.e. 3 feet of red and 3 feet of black), and priced far better for a specialty item like this than most outlets (3:1 is not that readily available).